Dataset Information

Comparative LC-MS analysis of two metronidazole resistant (M1,M2) and one revertant (M1NR) Giardia intestinalis strains with their parental strain (WB-C6)

ABSTRACT: I this study we analyzed three lines, two of which were created by UV- directed mutagenesis and showed increased levels of metronidazole tolerance (M1 and M2) and the third being a line that reverted spontanously to sensitive after several passages (M1NR) of M1 without metronidazole in the media. On the physiological side we analyzed the ability of these lines to reists metronidazole exposure and to encyst as well as their respective doublings times. At the same time we conducted a trasncriptomics and proteomics analysis to understand which exact changes lead to M1 and M2 being resistant while M1NR shows wildtype levels of metrondiazole sensitivty. We than compared these datasets to already existing datasets of other metrondiazole resistant lines and managed to identify a few core changes which are shared between all lines. In all lines proteins that are activating the drug are downregulated while proteins that are part of the oxidative stress response are found in higher abundance. On the other side these core changes are accompanied by a line specific set of changes, showing that there is more than one way for Giardia intestinalis to become resistant to metronidazole.

INSTRUMENT(S): Q Exactive Plus

ORGANISM(S): Giardia Lamblia Atcc 50803

DISEASE(S): Giardiasis

SUBMITTER: Sascha Krakovka

LAB HEAD: Staffan Svärd

PROVIDER: PXD027813 | Pride | 2022-01-26

REPOSITORIES: Pride

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Project description:Giardia causes more episodes of illness worldwide than any other parasite. It is a flagellated cyst-forming enteric pathogen that inhabits the lumen of the small intestine and although it is clear that more and less virulent strains do occur, pathogenesis and virulence of Giardia remains poorly understood. Identification of Giardia virulence factors is highly desirable since their expression would be the best indicator for determining disease outcome. The advent of quantitative proteomics has been timely in investigating which proteins are likely to be secreted virulence factors. Here we successfully apply such analyses to the whole parasite and to the supernatants derived from the parasite, in order to ascertain a repertoire of secreted proteins. In our initial analysis we compared replicates of Giardia cells and culture supernatants from the two major lineages which cause human disease – assemblage A and assemblage B. The genome of Giardia is believed to contain open reading frames which could encode as many as 6000 proteins. In our study we confirm expression of ~1600 proteins from each assemblage, the vast majority of which being common to both lineages. To look for actual enrichment of secreted proteins, we considered the ratio of proteins in the supernatant compared with the pellet. This simple method defines a small group of enriched proteins, putatively secreted at a steady state by cultured growing Giardia trophozoites of both assemblages. This secretome contains a high proportion annotated to have N’ terminus signal peptides, with some showing evidence of having recently evolved under strong positive selective pressure. The most abundant secreted proteins include known virulence factors such as the Cathepsin B cysteine proteases and members of a Giardia superfamily of Cysteine Rich Proteins which comprises VSPs, HCMPs and a new class of virulence factors, the Giardia Tenascins. Since we also find that physiological function of human enteric epithelial cells can be disrupted by soluble factors even in the absence of the trophozoites we are able to propose a straightforward model of Giardia pathogenesis incorporating key roles for the major Giardia derived soluble mediators.

Project description:Recent studies suggest the presence of both âclassically activatedâ M1 and âalternatively activatedâ M2 macrophages in human atherosclerotic tissue, yet due to the lack of validated markers the reported localization patterns of these macrophage phenotypes within plaques are ambiguous. In the present study, we searched for markers that indisputably can identify differentiated M1 and M2 macrophages independently of stimuli that affect the activation status of the two subpopulations. We used these validated markers to assess the presence of M1 and M2 macrophages in different zones of human carotid artery atherosclerotic plaques obtained from 12 patients. Using microarray and qPCR technology we show that the frequently used macrophage subpopulation markers MCP-1 and CD206 do not discriminate between M1 and M2 macrophages. However, we confirm the subtype specificity of the classical M2 marker CD163 and we report that the genes INHBA and DSP (both M1) and SEPP1 and MARCKS (both M2) are highly suitable for macrophage phenotyping. mRNA expression of the pan-macrophage marker CD68 in the shoulder zones of the plaques and in adjacent tissue segments correlated positively with mRNA expression levels of SEPP1, MARCKS and CD163 (r=0.86, 0.94 and 0.96, and r= 0.86, 0.98 and 0.69, respectively) but not with the expression of the M1 markers DSP and INHBA. In contrast, mRNA expression of CD68 in the core of the plaques correlated positively with expression of DSP and INHBA (r=0.73 and 0.49) but not with SEPP1, MARCKS and CD163. These findings suggest that M1 macrophages predominate in the core of human carotid atherosclerotic plaques while M2 macrophages prevail at the periphery of the plaque. Keywords: Expression profiling by array Monocytes from healthy volunteers were differentiated into M1 and M2 macrophages by incubation with granulocyte-macrophage colony-stimulating factor (GM-CSF) or macrophage colony-stimulating factor (M-CSF), respectively. After 5 days cells were exposed to oxidized LDL. Total RNA was isolated and subjected to gene expression profiling.

Dataset Information

Comparative LC-MS analysis of two metronidazole resistant (M1,M2) and one revertant (M1NR) Giardia intestinalis strains with their parental strain (WB-C6)

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